This invention relates to a scanning probe microscope.
Atomic force microscopes (AFM) have been studied and are expected to serve as novel surface topological observing means since devised by an inventor of the STM, G. Binnig et al. (Physical Review Letters vol. 56 p930 1986). The underlying principle is that an interatomic force acting between a detection tip fully sharpened at a tip and a sample is measured as a displacement of a cantilever to which the detection tip is mounted. A sample surface is scanned while maintaining the displacement between the sample surface and the cantilever constant so that the sample surface is measured in topology using as topological information a control signal applied to maintain the displacement in the cantilever. In recent years, besides atomic force, the application field has broadened to measure various physical characteristics such as magnetic force and surface potential force. Such instruments are generally referred to as scanning probe microscopes.
The cantilever in a scanning probe microscope is fabricated by a semiconductor manufacturing process and has a size of approximately 0.3-10.5 mm in thickness, 1.3-1.6 mm in width and 3 mm in length. Of the scanning probe microscopes currently being produced, there are many scanning probe microscopes having an intermediate part referred to as a lever holder or the like so that the cantilever attached to the lever holder is thereafter mounted onto the probe microscope main body. However, because the presence of an intermediate part such as the lever holder is disadvantageous in automation, there is a scheme in which the cantilever is directly attached to a cantilever attaching portion at a tip of a fine movement mechanism rather than through the use of a lever holder. For cantilever fixing in such a case, the vacuum suction scheme is adopted in view of miniaturization, automation, and the like.
FIG. 4 is a side sectional view of a conventional cantilever supply mechanism. FIG. 5 is a top view of the conventional cantilever supply mechanism. Conventionally, the cantilever supply mechanism for supplying a cantilever to the cantilever attaching portion has been formed of a metal block having the same angle as the slant angle of the cantilever attaching portion and mountable with a plurality of cantilevers arranged. The individual cantilever 1 is set up in a positioning groove by tweezers or the like.
The positional coordinates of respective cantilevers 1 are stored in a controller. The area where the cantilevers are to be mounted is slanted but structured such that the cantilever 1 is prevented from falling out by an anti-slip stopper portion 40. In the case the cantilever 1 is desired to be fixed more positively, a pipe port 41 may be connected with a vacuum section source and suction-fixing may be used.
In the cantilever attaching procedure, first an XY stage is moved to a stored coordinate and moved immediately above a cantilever to be replaced in a cantilever attaching portion. Next, a Z stage is moved to approach the cantilever attaching portion and the cantilever to a distance at which the cantilever can be vacuum-attached. In an apparatus trial-manufactured, the distance was generally 0.5 mm or less. Finally, the vacuum suction source is actuated to attach the cantilever onto the cantilever attaching portion, thus ending attaching operation.
However, there are the following problems in the cantilever attaching operation performed by the conventional cantilever supply mechanism.
(1) Because the vacuum suction source is actuated in a state where the cantilever attaching portion and the cantilever are not yet in close contact, when the cantilever is attracted by the cantilever attaching portion, the dust floating around the areas is also attracted. The dust is caught between the cantilever and the cantilever attaching portion, possibly causing instability.
(2) Vacuum suction is made in a state where the cantilever attaching portion and the cantilever are not yet closely contacted, the cantilever is attracted while it is horizontally or rotationally deviated and jumps up to the cantilever attaching portion, resulting in poor reproducibility in cantilever attaching position.
Therefore, it is an object of this invention to obtain a novel cantilever supply mechanism and a method of attaching the cantilever in order to solve such conventional problems
In order to solve the above problems, in the present invention a cantilever holding portion of a cantilever holding mechanism of a cantilever supply mechanism is structured by a base, cantilever fixing means disposed on the base, and an elastically deformable material, or a material having elasticity disposed on the base. When the cantilever is to be attached to the cantilever attaching portion, the Z stage is moved until the cantilever attaching portion comes into contact with the cantilever and is further moved a predetermined quantity after such contact.
In the cantilever supply mechanism structured as described above, when a cantilever is attached, the Z stage is operated to bring into contact the cantilever attaching portion with the cantilever. After contact, the Z stage is further operated whereby the cantilever attaching portion can be brought into complete contact with the cantilever. The physical interference in operation after such contact is absorbed by elastic deformation in the elastic material which is preferably an adhesive and a pressure sensitive conductive elastomer. By vacuum attaching the cantilever in a state of full and close contact, this solves the problem of attracting dust and the problem of positional deviation of the cantilever upon attachment.